/* syscalls.h 
 * 	Nachos system call interface.  These are Nachos kernel operations
 * 	that can be invoked from user programs, by trapping to the kernel
 *	via the "syscall" instruction.
 *
 *	This file is included by user programs and by the Nachos kernel. 
 *
 * Copyright (c) 1992-1993 The Regents of the University of California.
 * All rights reserved.  See copyright.h for copyright notice and limitation 
 * of liability and disclaimer of warranty provisions.
 */

#ifndef SYSCALLS_H
#define SYSCALLS_H

#include "copyright.h"

/* system call codes -- used by the stubs to tell the kernel which system call
 * is being asked for
 */
#define SC_Halt		   0
#define SC_Exit		   1
#define SC_Exec		   2
#define SC_Join		   3
#define SC_Create	   4
#define SC_Open		   5
#define SC_Read		   6
#define SC_Write	   7
#define SC_Close	   8
#define SC_Fork		   9
#define SC_Yield	   10
#define SC_CreateLock  11
#define SC_CreateCV    12
#define SC_Acquire 	   13
#define SC_Release	   14
#define SC_Wait		   15
#define SC_Signal	   16
#define SC_Broadcast   17
#define SC_DestroyLock 18
#define SC_DestroyCV   19
#define SC_SWrite      20
#define SC_ToString    21
#define SC_Append      22
#define SC_Rand        23

#define SC_CreateIntMV       25
#define SC_AlterIntMV        26
#define SC_RetrieveIntMV     27
#define SC_DestroyIntMV      28


#define ServerForwardedMessage 29
#define ServerHeartbeat 30

#define SC_WriteAll		31

#define NUMBER_OF_SERVERS 1

#define MAXFILENAME 256

#ifndef IN_ASM

/* The system call interface.  These are the operations the Nachos
 * kernel needs to support, to be able to run user programs.
 *
 * Each of these is invoked by a user program by simply calling the 
 * procedure; an assembly language stub stuffs the system call code
 * into a register, and traps to the kernel.  The kernel procedures
 * are then invoked in the Nachos kernel, after appropriate error checking, 
 * from the system call entry point in exception.cc.
 */

/* Stop Nachos, and print out performance stats */
void Halt();		
 

/* Address space control operations: Exit, Exec, and Join */

/* This user program is done (status = 0 means exited normally). */
void Exit(int status);	

/* A unique identifier for an executing user program (address space) */
typedef int SpaceId;	
 
/* Run the executable, stored in the Nachos file "name", and return the 
 * address space identifier
 */
SpaceId Exec(char *name, int lengthOfPath);
 
/* Only return once the the user program "id" has finished.  
 * Return the exit status.
 */
int Join(SpaceId id); 	
 

/* File system operations: Create, Open, Read, Write, Close
 * These functions are patterned after UNIX -- files represent
 * both files *and* hardware I/O devices.
 *
 * If this assignment is done before doing the file system assignment,
 * note that the Nachos file system has a stub implementation, which
 * will work for the purposes of testing out these routines.
 */
 
/* A unique identifier for an open Nachos file. */
typedef int OpenFileId;	

/* when an address space starts up, it has two open files, representing 
 * keyboard input and display output (in UNIX terms, stdin and stdout).
 * Read and Write can be used directly on these, without first opening
 * the console device.
 */

#define ConsoleInput	0  
#define ConsoleOutput	1  
 
/* Create a Nachos file, with "name" */
void Create(char *name, int size);

/* Open the Nachos file "name", and return an "OpenFileId" that can 
 * be used to read and write to the file.
 */
OpenFileId Open(char *name, int size);

/* Write "size" bytes from "buffer" to the open file. */
void Write(char *buffer, int size, OpenFileId id);

/* special write that can print two values*/
void SWrite(char *buffer, int size, int value1, int value2);

/* special write that can print as multiple values*/
void WriteAll(char *buffer, int *sizes, int *inputs);

/* Read "size" bytes from the open file into "buffer".  
 * Return the number of bytes actually read -- if the open file isn't
 * long enough, or if it is an I/O device, and there aren't enough 
 * characters to read, return whatever is available (for I/O devices, 
 * you should always wait until you can return at least one character).
 */
int Read(char *buffer, int size, OpenFileId id);

/* Close the file, we're done reading and writing to it. */
void Close(OpenFileId id);



/* User-level thread operations: Fork and Yield.  To allow multiple
 * threads to run within a user program. 
 */

/* Fork a thread to run a procedure ("func") in the *same* address space 
 * as the current thread.
 */
void Fork(void (*func)(), char* threadName, int threadNameLength);

/* Yield the CPU to another runnable thread, whether in this address space 
 * or not. 
 */
void Yield();

/* LOCK OPERATIONS */

/* Creates a lock for the system call caller */
int CreateLock(char* lockName, int numberOfChars);

/* Acquire a lock */
int LockAcquire(int lockNumber);

/* Release a lock */
int LockRelease(int lockNumber);

/* Destroys lock */
int LockDestroy(int lockToDestroy);

/* CONDITION OPERATIONS */

/* Creates a Condition instance */
int CreateCV(char* cvName, int numberOfChars);

/* CV Wait */
void CVWait(int cvNumber, int lockToWaitOn);

/* CV Signal */
void CVSignal(int cvNumber, int lockToSignal);

/* CV Broadcast */
void CVBroadcast(int cvNumber, int lockToBroadcast);

/* Destroy CV */
void CVDestroy(int cvToDestroy);

/* Execute a process */
void ProcessExec(unsigned int addrToExecutable);

/* Exit a process */
void ProcessExit();	

/* Extras */
void ToString(char *buffer, int length, int number);
int Append(char *string1, char *string2, int *sizes);
int Rand(int low, int high);

/* int array Monitor variable methods */
int  CreateIntMV(char* MVname, int length, int arraySize);
int  AlterIntMV(int mvId, int mvIndex, int newValue);
int  RetrieveIntMV(int mvId, int mvIndex);
void DestroyIntMV(int mvId, int length);

#endif /* IN_ASM */

#endif /* SYSCALL_H */
